NEW YORK-- Ehud Barak's term as Israeli prime minister was among the shortest in Israeli history, but in just 19 months he succeeded in altering the strategic landscape of the Middle East and recasting the terms of Israeli political debate.

Barak's most recognized accomplishment was the withdrawal of Israeli forces from southern Lebanon after a bloody 18-year engagement.

In that sense, Barak and the man who defeated him Tuesday, Likud Party leader Ariel Sharon, stand as bookends in Israeli history: Sharon was the man who led Israeli forces into Lebanon, Barak the one who took them out.

The ultimate verdict on the withdrawal is still out, however, as Hezbollah militants continue to harass Israel along its northern border and many Palestinians consider Hezbollah's war tactics a model for the West Bank and Gaza Strip.

Still, Barak's bold move ended the slow bloodletting of Israeli youth in southern Lebanon, removed a strategic card from the Syrian arsenal and erased a major stain on Israel's international reputation.

On the peace process, Barak is scorned by many Israelis for his willingness to consider extraordinary concessions even in the face of Palestinian violence.

History, however, may judge Barak's efforts differently.

By going further than any other Israeli leader in his pursuit of final peace agreements with the Palestinians and Syrians-only to be met with intransigence and rejection-Barak's greatest achievement may have been to pull the masks off Israel's "peace partners" as no right winger ever could.

Criticized for "zigzagging" on important policies in office, Barak displayed a remarkable consistency in his attitude toward the peace process.

Despite his courage in touching what he called the "living heart" of the Israeli-Palestinian conflict, he always was skeptical of the Oslo process and never really trusted Palestinian intentions.

From his days as army chief of staff when the 1993 Oslo accord was negotiated under Prime Minster Yitzhak Rabin, Barak objected to what he considered a major weakness of the peace process: the focus on interim agreements under which Israel gradually surrendered its bargaining chips without having an idea of the Palestinian endgame.

After becoming prime minister, Barak refused to implement the remaining withdrawals demanded of Israel, and instead sought to go straight to a final agreement, even if it entailed deeper Israeli concessions.

While that final agreement proved beyond his grasp, Barak-unlike even his predecessor, the Likud's Benjamin Netanyahu-did not turn over even one acre of land to Palestinian control.

The major concessions Barak reportedly was willing to offer-dividing Jerusalem, giving the Palestinians unprecedented control of the Temple Mount, relinquishing virtually all the land Israel won in the 1967 Six-Day War -destroyed many of Israel's sacred cows of the last three decades, and seem likely to set the parameters of Israeli political debate in the coming years.

Yet those concessions were not enough for the Palestinians.

Palestinian Authority President Yasser Arafat continued to hold out for the "right" of some 3 million to 4 million Arab refugees and their descendants to return to homes they left in 1948, a demand that would amount to demographic suicide for Israel.

And Arafat refused to countenance any measure of Israeli control of holy sites in Jerusalem, denying any Jewish historical tie to the Temple Mount.

Arafat's response to Barak's offer was the low-intensity war that has engulfed the Palestinian territories since late September. In effect, the Palestinians overthrew Barak, just as they overthrew his two predecessors.

With his return to violence, Arafat more than any other individual is responsible for the victory of Sharon, a man the Palestinians profess to hate.

That lesson is instructive for what it says of Palestinian intentions, and points to the greatest danger now facing Israel.

The Palestinian preference for a "hard-line" Israeli leader appears to confirm the charge that Arafat is not truly interested in a peace agreement -- but knows that under a right-wing government, Israel is likely to take the international blame for any tension.

The return to the international doghouse Israel inhabited during Netanyahu's term would be a significant diplomatic blow.

More important, however, is the danger of a rift within Israeli society if the left also returns to blaming Israel for any deterioration in the peace process.

Because of the concessions he was willing to make, Barak restored for most Israelis a belief in the justness of their cause, a belief that such a war truly was not responsible for the violence of recent months.

That's no small feat, given Israelis' remarkable penchant for self-flagellation. If war comes on Sharon's watch, it's far from clear that it will find Israel with such unity of purpose.

What little Sharon has revealed of his diplomatic plan does not augur well for the prospect of a peace agreement.

Given the rehabilitation of other once-disgraced Israeli leaders-Sharon and Netanyahu come quickly to mind-it's quite possible that the Israeli and Palestinian publics will soon clamor to have Barak back.